This application proposes to establish a clinical research group at the University of California, San Francisco to participate in an interactive network conducting studies of novel therapeutic approaches to asthma and disseminating its findings to the practicing community. The need for such a network is demonstrated by epidemiologic data showing increases in the mortality, morbidity, prevalence, and economic impact of this common disease, clinical and basic research studies showing that asthma is linked to the cells and chemicals that mediate inflammation in the airways, and the accelerating rate of development of new, potentially highly effective, but also potentially costly treatments. Defining the place of these new therapies will require collaborative, multi-center studies examining large numbers of subjects reflecting the diversity of the U.S. population. This application specifically proposes to assemble the UCSF clinical research group from clinical scientists who have substantial experience in basic and clinical research on asthma, and it proposes to expand an established database of patients with asthma interested in participating in clinical research studies. Two protocols are proposed to illustrate possible multi-center trials that could be conducted by a national Asthma Clinical Research Network. The first examines a new agent, a 5- lipoxygenase inhibitor, and two current standard therapies, inhaled beta- agonists and inhaled corticosteroids, comparing not only their efficacy in reducing symptoms but also their effects on markers of inflammation in the airways and the rate of recurrence of symptoms after therapy is discontinued. The second protocol proposes to examine the effects of therapy on mucus hypersecretion, an important abnormality in asthma that only recently was made accessible to study by advances in techniques for obtaining airway secretions and for quantitating the chemical components of airway mucus. The protocol proposes to examine a subgroup of asthmatic patients who complain of constant sputum production, comparing the effects of an inhaled corticosteroid and placebo on symptoms of sputum production and airflow obstruction and also on the quantities of different components of airway mucus in samples of airway secretions.